oil becomes permanently thicker in cold weather?

[douh]

I just found this site, and I must say I'm impressed. Avenue Q isn't quite right about the use of the internet.

In the 'oil university' there is mention of 'Motor oil becomes permanently thicker with exposure to northerly winter type weather. This is more of a problem to mineral based oils.'

I've spent some time looking into this and can't find any other references that this is permanent damage. Some oils [possibly those from paraffinic crude manufactured using poor processes] may have some ability to crystallize at cold temperatures, but these would melt when reheated. This would be like honey or olive oil crystallizing in the winter months [or fridge] and going back to the initial state when warmed. I've also documented this type of crystallization occurring in epoxy resins among other things at work.

Is there a white paper or other reputable article that documents what is actually occurring, possibly breaking an emulsion? or is this something that is not a concern, with modern oils.

I'm due for an oil change in the truck and winter is not quite gone. Should I hold off for another month or is this a reason to switch to a synthetic?

Thanks for your help.

 

[MolaKule]

Quote:
[Does] oil become permanently thicker in cold weather


Oil does not have a memory; it is a dynamic fluid and it's viscosity depends on several conditions:

1. Original viscosity and formulation
2. fuel dilution can thin it out
3. Entrained moisture can form cold sludge and thicken it up
4. oxidation can cause an oil to thicken, especially at high temperatures
5. driving conditions

If you drive the vehicle so it gets up to temperature you will usually drive off any moisture.

So no it does not get permanently thicker in cold weather.

Modern oils do a pretty good job of handling any moisture.

 

[friendly_jacek]

There is an issue with some diesel oils becoming very thick in cold weather when exposed to biofuel. Some kind of adverse reaction of biofuel with certain types of VII.

Some engines were damaged due to that in cold weather starts. Not sure it that applies to gas and North America to be honest.

 

[MolaKule]

Quote:
There is an issue with some diesel oils becoming very thick in cold weather when exposed to biofuel. Some kind of adverse reaction of biofuel with certain types of VII.



That's probably due to the veggy oil (most likely soybean oil in the fuel) polymerizing in the oil.

But since the OP asked the question in the PCMO gasoline section, I assumed he was referring to gasoline engine oils.

 

[volk06]

Originally Posted By: MolaKule
Quote:
There is an issue with some diesel oils becoming very thick in cold weather when exposed to biofuel. Some kind of adverse reaction of biofuel with certain types of VII.



That's probably due to the veggy oil (most likely soybean oil in the fuel) polymerizing in the oil.

But since the OP asked the question in the PCMO gasoline section, I assumed he was referring to gasoline engine oils.


Yes. Biodiesel gels very easily. Different biodiesel basestocks yield different cold properties. Animal fat has the worst cold performance, soy is in the middle, and canola based biodiesel has some of the better cold performance specs and properties. I'd be curious to see how these would individually affect the oil compared to other bio based stocks.

 

[REDDOG]

Molakule,

How dependant are modern oils on pour point depressants? Are pour point depressants "used up" by exposure to the cold?

Thanks

 

[douh]

My primary interest is with a gasoline engine, but interesting info on the biodiesel.

 

[aquariuscsm]

Originally Posted By: douh
'Motor oil becomes permanently thicker with exposure to northerly winter type weather. This is more of a problem to mineral based oils.'


WRONGGGG. Doesn`t happen.

 

[MolaKule]

Quote:
How dependant are modern oils on pour point depressants? Are pour point depressants "used up" by exposure to the cold?


Very little, actually. Now of course the mineral oils will have more Pour Point Depressants (PPD) than will oils with synthetic bases.

The literature shows that the most used depressants, polymethylacrylates, or PMA's, are very stable over the life of the oil.

 

[Garak]

Originally Posted By: MolaKule
The literature shows that the most used depressants, polymethylacrylates, or PMA's, are very stable over the life of the oil.


Question for you, Mola - how well do the cold cranking specifications of modern PCMOs (synthetic and conventional) hold up over the length of the OCI? We've all heard the talk about the cold cranking specs getting worse over an OCI, but I'm wondering how the modern PCMOs fare compared to the multigrades of the past.

 

[MolaKule]

Modern oils fare much better because of the better base oils and improved anti-oxidants.

 

[REDDOG]

Thanks, Molakule! Very good to know!

 

[Garak]

Thanks, Mola!

 

[INDYMAC]

I have heard of gelation damage occurring from cold weather. But API certification requires gelation indexs low enough to prevent this from happening. That being said, I still try to do oil changes in the spring and fall (just in case!).

http://www.imakenews.com/lng/e_article000057673.cfm